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Concina G, Gurgone A, Boggio EM, Raspanti A, Pizzo R, Morello N, Castroflorio E, Pizzorusso T, Sacchetti B, Giustetto M. Stabilizing Immature Dendritic Spines in the Auditory Cortex: A Key Mechanism for mTORC1-Mediated Enhancement of Long-Term Fear Memories. J Neurosci 2023; 43:8744-8755. [PMID: 37857485 PMCID: PMC10727119 DOI: 10.1523/jneurosci.0204-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 08/30/2023] [Accepted: 09/04/2023] [Indexed: 10/21/2023] Open
Abstract
Mammalian target of rapamycin (mTOR) pathway has emerged as a key molecular mechanism underlying memory processes. Although mTOR inhibition is known to block memory processes, it remains elusive whether and how an enhancement of mTOR signaling may improve memory processes. Here we found in male mice that the administration of VO-OHpic, an inhibitor of the phosphatase and tensin homolog (PTEN) that negatively modulates AKT-mTOR pathway, enhanced auditory fear memory for days and weeks, while it left short-term memory unchanged. Memory enhancement was associated with a long-lasting increase in immature-type dendritic spines of pyramidal neurons into the auditory cortex. The persistence of spine remodeling over time arose by the interplay between PTEN inhibition and memory processes, as VO-OHpic induced only a transient immature spine growth in the somatosensory cortex, a region not involved in long-term auditory memory. Both the potentiation of fear memories and increase in immature spines were hampered by rapamycin, a selective inhibitor of mTORC1. These data revealed that memory can be potentiated over time by the administration of a selective PTEN inhibitor. In addition to disclosing new information on the cellular mechanisms underlying long-term memory maintenance, our study provides new insights on the molecular processes that aid enhancing memories over time.SIGNIFICANCE STATEMENT The neuronal mechanisms that may help improve the maintenance of long-term memories are still elusive. The inhibition of mammalian-target of rapamycin (mTOR) signaling shows that this pathway plays a crucial role in synaptic plasticity and memory formation. However, whether its activation may strengthen long-term memory storage is unclear. We assessed the consequences of positive modulation of AKT-mTOR pathway obtained by VO-OHpic administration, a phosphatase and tensin homolog inhibitor, on memory retention and underlying synaptic modifications. We found that mTOR activation greatly enhanced memory maintenance for weeks by producing a long-lasting increase of immature-type dendritic spines in pyramidal neurons of the auditory cortex. These results offer new insights on the cellular and molecular mechanisms that can aid enhancing memories over time.
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Affiliation(s)
- Giulia Concina
- Department of Neuroscience, University of Turin, Turin, 10125, Italy
| | - Antonia Gurgone
- Department of Neuroscience, University of Turin, Turin, 10125, Italy
| | - Elena M Boggio
- Institute of Neuroscience, National Research Council, Pisa, 56124, Italy
| | | | - Riccardo Pizzo
- Department of Neuroscience, University of Turin, Turin, 10125, Italy
| | - Noemi Morello
- Department of Neuroscience, University of Turin, Turin, 10125, Italy
| | | | - Tommaso Pizzorusso
- Institute of Neuroscience, National Research Council, Pisa, 56124, Italy
- Scuola Normale Superiore, Biology Laboratory BIO@SNS, Pisa, 56124, Italy
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Montero-Atalaya M, Expósito S, Muñoz-Arnaiz R, Makarova J, Bartolomé B, Martín E, Moreno-Arribas MV, Herreras O. A dietary polyphenol metabolite alters CA1 excitability ex vivo and mildly affects cortico-hippocampal field potential generators in anesthetized animals. Cereb Cortex 2023; 33:10411-10425. [PMID: 37550066 PMCID: PMC10545443 DOI: 10.1093/cercor/bhad292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 07/17/2023] [Accepted: 07/18/2023] [Indexed: 08/09/2023] Open
Abstract
Dietary polyphenols have beneficial effects in situations of impaired cognition in acute models of neurodegeneration. The possibility that they may have a direct effect on the electrical activity of neuronal populations has not been tested. We explored the electrophysiological action of protocatechuic acid (PCA) on CA1 pyramidal cells ex vivo and network activity in anesthetized female rats using pathway-specific field potential (FP) generators obtained from laminar FPs in cortex and hippocampus. Whole-cell recordings from CA1 pyramidal cells revealed increased synaptic potentials, particularly in response to basal dendritic excitation, while the associated evoked firing was significantly reduced. This counterintuitive result was attributed to a marked increase of the rheobase and voltage threshold, indicating a decreased ability to generate spikes in response to depolarizing current. Systemic administration of PCA only slightly altered the ongoing activity of some FP generators, although it produced a striking disengagement of infraslow activities between the cortex and hippocampus on a scale of minutes. To our knowledge, this is the first report showing the direct action of a dietary polyphenol on electrical activity, performing neuromodulatory roles at both the cellular and network levels.
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Affiliation(s)
- Marta Montero-Atalaya
- Dept Biotecnología y Microbiología de Alimentos, Institute of Food Science Research (CIAL), CSIC-UAM, c/Nicolás Cabrera, 9, 28049 Madrid, Spain
| | - Sara Expósito
- Dept Neurociencia Translacional, Cajal Institute, CSIC, Av Doctor Arce 37, 28002 Madrid, Spain
| | - Ricardo Muñoz-Arnaiz
- Dept Neurociencia Translacional, Cajal Institute, CSIC, Av Doctor Arce 37, 28002 Madrid, Spain
| | - Julia Makarova
- Dept Neurociencia Translacional, Cajal Institute, CSIC, Av Doctor Arce 37, 28002 Madrid, Spain
| | - Begoña Bartolomé
- Dept Biotecnología y Microbiología de Alimentos, Institute of Food Science Research (CIAL), CSIC-UAM, c/Nicolás Cabrera, 9, 28049 Madrid, Spain
| | - Eduardo Martín
- Dept Neurociencia Translacional, Cajal Institute, CSIC, Av Doctor Arce 37, 28002 Madrid, Spain
| | - María Victoria Moreno-Arribas
- Dept Biotecnología y Microbiología de Alimentos, Institute of Food Science Research (CIAL), CSIC-UAM, c/Nicolás Cabrera, 9, 28049 Madrid, Spain
| | - Oscar Herreras
- Dept Neurociencia Translacional, Cajal Institute, CSIC, Av Doctor Arce 37, 28002 Madrid, Spain
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Estévez-Silva HM, Cuesto G, Romero N, Brito-Armas JM, Acevedo-Arozena A, Acebes Á, Marcellino DJ. Pridopidine Promotes Synaptogenesis and Reduces Spatial Memory Deficits in the Alzheimer's Disease APP/PS1 Mouse Model. Neurotherapeutics 2022; 19:1566-1587. [PMID: 35917088 PMCID: PMC9606189 DOI: 10.1007/s13311-022-01280-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2022] [Indexed: 10/16/2022] Open
Abstract
Sigma-1 receptor agonists have recently gained a great deal of interest due to their anti-amnesic, neuroprotective, and neurorestorative properties. Compounds such as PRE-084 or pridopidine (ACR16) are being studied as a potential treatment against cognitive decline associated with neurodegenerative disease, also to include Alzheimer's disease. Here, we performed in vitro experiments using primary neuronal cell cultures from rats to evaluate the abilities of ACR16 and PRE-084 to induce new synapses and spines formation, analyzing the expression of the possible genes and proteins involved. We additionally examined their neuroprotective properties against neuronal death mediated by oxidative stress and excitotoxicity. Both ACR16 and PRE-084 exhibited a concentration-dependent neuroprotective effect against NMDA- and H2O2-related toxicity, in addition to promoting the formation of new synapses and dendritic spines. However, only ACR16 generated dendritic spines involved in new synapse establishment, maintaining a more expanded activation of MAPK/ERK and PI3K/Akt signaling cascades. Consequently, ACR16 was also evaluated in vivo, and a dose of 1.5 mg/kg/day was administered intraperitoneally in APP/PS1 mice before performing the Morris water maze. ACR16 diminished the spatial learning and memory deficits observed in APP/PS1 transgenic mice via PI3K/Akt pathway activation. These data point to ACR16 as a pharmacological tool to prevent synapse loss and memory deficits associated with Alzheimer's disease, due to its neuroprotective properties against oxidative stress and excitotoxicity, as well as the promotion of new synapses and spines through a mechanism that involves AKT and ERK signaling pathways.
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Affiliation(s)
- Héctor M Estévez-Silva
- Departamento de Ciencias Médicas Básicas, Instituto de Tecnologías Biomédicas (ITB), Universidad de La Laguna, Tenerife, Spain
- Department of Integrative Medical Biology, Umeå University, Umeå, Sweden
| | - Germán Cuesto
- Departamento de Ciencias Médicas Básicas, Instituto de Tecnologías Biomédicas (ITB), Universidad de La Laguna, Tenerife, Spain
| | - Ninovska Romero
- Departamento de Ciencias Médicas Básicas, Instituto de Tecnologías Biomédicas (ITB), Universidad de La Laguna, Tenerife, Spain
| | - José Miguel Brito-Armas
- Unidad de Investigación, Hospital Universitario de Canarias, ITB-ULL/CIBERNED, Tenerife, Spain
| | - Abraham Acevedo-Arozena
- Unidad de Investigación, Hospital Universitario de Canarias, ITB-ULL/CIBERNED, Tenerife, Spain
| | - Ángel Acebes
- Departamento de Ciencias Médicas Básicas, Instituto de Tecnologías Biomédicas (ITB), Universidad de La Laguna, Tenerife, Spain.
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4
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Hashiesh HM, Sharma C, Goyal SN, Sadek B, Jha NK, Kaabi JA, Ojha S. A focused review on CB2 receptor-selective pharmacological properties and therapeutic potential of β-caryophyllene, a dietary cannabinoid. Biomed Pharmacother 2021; 140:111639. [PMID: 34091179 DOI: 10.1016/j.biopha.2021.111639] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 04/12/2021] [Accepted: 04/19/2021] [Indexed: 02/06/2023] Open
Abstract
The endocannabinoid system (ECS), a conserved physiological system emerged as a novel pharmacological target for its significant role and potential therapeutic benefits ranging from neurological diseases to cancer. Among both, CB1 and CB2R types, CB2R have received attention for its pharmacological effects as antioxidant, anti-inflammatory, immunomodulatory and antiapoptotic that can be achieved without causing psychotropic adverse effects through CB1R. The ligands activate CB2R are of endogenous, synthetic and plant origin. In recent years, β-caryophyllene (BCP), a natural bicyclic sesquiterpene in cannabis as well as non-cannabis plants, has received attention due to its selective agonist property on CB2R. BCP has been well studied in a variety of pathological conditions mediating CB2R selective agonist property. The focus of the present manuscript is to represent the CB2R selective agonist mediated pharmacological mechanisms and therapeutic potential of BCP. The present narrative review summarizes insights into the CB2R-selective pharmacological properties and therapeutic potential of BCP such as cardioprotective, hepatoprotective, neuroprotective, nephroprotective, gastroprotective, chemopreventive, antioxidant, anti-inflammatory, and immunomodulator. The available evidences suggest that BCP, can be an important candidate of plant origin endowed with CB2R selective properties that may provide a pharmacological rationale for its pharmacotherapeutic application and pharmaceutical development like a drug. Additionally, given the wide availability in edible plants and dietary use, with safety, and no toxicity, BCP can be promoted as a nutraceutical and functional food for general health and well-being. Further, studies are needed to explore pharmacological and pharmaceutical opportunities for therapeutic and preventive applications of use of BCP in human diseases.
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Affiliation(s)
- Hebaallah Mamdouh Hashiesh
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Charu Sharma
- Department of Internal Medicine, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Sameer N Goyal
- Shri Vile Parle Kelvani Mandal's Institute of Pharmacy, Dhule 424001, Maharashtra, India
| | - Bassem Sadek
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Niraj Kumar Jha
- Department of Biotechnology, School of Engineering & Technology, Sharda University, Greater Noida, Uttar Pradesh 201310, India
| | - Juma Al Kaabi
- Department of Internal Medicine, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Shreesh Ojha
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates; Zayed Bin Sultan Al Nahyan Center for Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates.
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5
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Vasques JF, Gonçalves RGDJ, Gomes ALT, Campello-Costa P, Serfaty CA, Faria-Melibeu ADC. Signaling pathways modulated by monocular enucleation in the superior colliculus of juvenile rats. Int J Dev Neurosci 2021; 81:249-258. [PMID: 33544920 DOI: 10.1002/jdn.10095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/27/2021] [Accepted: 01/30/2021] [Indexed: 11/06/2022] Open
Abstract
Monocular eye enucleation (ME) is a classical paradigm to induce neural plasticity in retinal ganglion cells (RGCs) axons from the intact eye, especially when performed within the critical period of visual system development. However, the precise mechanisms underlying the axonal sprouting and synaptogenesis seen in this model remain poorly understood. In the present work, we investigated the temporal alterations in phosphorylation of three kinases related to axonal growth and synaptogenesis-GSK3β (an important repressor of axonal outgrowth), AKT, and ERK-in superior colliculus of rats submitted to ME during early postnatal development. Western blotting analysis showed an increase in pGSK3β, the inactive form of this enzyme, 24 and 48 hr after ME. Accordingly, an increase in pERK levels was detected 24 hr after ME, indicating that phosphorylation of these enzymes might be related to axonal reorganization induced by ME. Interestingly, AKT phosphorylation was increased just 1 week after ME, suggesting it may be involved in the stabilization of newly formed synapses, rising from the axonal reorganization of remaining eye. A better understanding of how signaling pathways are modulated in a model of intense axonal sprouting can highlight possible therapeutic targets in RGCs injuries in adult individuals, where axonal regrowth is nearly absent.
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Affiliation(s)
- Juliana Ferreira Vasques
- Programa de Neurociências, Departamento de Neurobiologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil.,Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Renata Guedes de Jesus Gonçalves
- Programa de Neurociências, Departamento de Neurobiologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil.,Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ana Lucia Tavares Gomes
- Programa de Neurociências, Departamento de Neurobiologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil
| | - Paula Campello-Costa
- Programa de Neurociências, Departamento de Neurobiologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil
| | - Claudio Alberto Serfaty
- Programa de Neurociências, Departamento de Neurobiologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil
| | - Adriana da Cunha Faria-Melibeu
- Programa de Neurociências, Departamento de Neurobiologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil
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6
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Arnés M, Romero N, Casas-Tintó S, Acebes Á, Ferrús A. PI3K activation prevents Aβ42-induced synapse loss and favors insoluble amyloid deposit formation. Mol Biol Cell 2019; 31:244-260. [PMID: 31877058 PMCID: PMC7183762 DOI: 10.1091/mbc.e19-05-0303] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Excess of Aβ42 peptide is considered a hallmark of the disease. Here we express the human Aβ42 peptide to assay the neuroprotective effects of PI3K in adult Drosophila melanogaster. The neuronal expression of the human peptide elicits progressive toxicity in the adult fly. The pathological traits include reduced axonal transport, synapse loss, defective climbing ability and olfactory perception, as well as lifespan reduction. The Aβ42-dependent synapse decay does not involve transcriptional changes in the core synaptic protein encoding genes bruchpilot, liprin and synaptobrevin. All toxicity features, however, are suppressed by the coexpression of PI3K. Moreover, PI3K activation induces a significant increase of 6E10 and thioflavin-positive amyloid deposits. Mechanistically, we suggest that Aβ42-Ser26 could be a candidate residue for direct or indirect phosphorylation by PI3K. Along with these in vivo experiments, we further analyze Aβ42 toxicity and its suppression by PI3K activation in in vitro assays with SH-SY5Y human neuroblastoma cell cultures, where Aβ42 aggregation into large insoluble deposits is reproduced. Finally, we show that the Aβ42 toxicity syndrome includes the transcriptional shut down of PI3K expression. Taken together, these results uncover a potential novel pharmacological strategy against this disease through the restoration of PI3K activity.
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Affiliation(s)
| | - Ninovska Romero
- Department of Basic Medical Sciences, Institute of Biomedical Technologies, University of La Laguna, Tenerife 38200, Spain
| | | | - Ángel Acebes
- Cajal Institute (CSIC), Madrid 28002, Spain.,Department of Basic Medical Sciences, Institute of Biomedical Technologies, University of La Laguna, Tenerife 38200, Spain
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7
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Mata G, Radojević M, Fernandez-Lozano C, Smal I, Werij N, Morales M, Meijering E, Rubio J. Automated Neuron Detection in High-Content Fluorescence Microscopy Images Using Machine Learning. Neuroinformatics 2019; 17:253-269. [PMID: 30215167 DOI: 10.1007/s12021-018-9399-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The study of neuronal morphology in relation to function, and the development of effective medicines to positively impact this relationship in patients suffering from neurodegenerative diseases, increasingly involves image-based high-content screening and analysis. The first critical step toward fully automated high-content image analyses in such studies is to detect all neuronal cells and distinguish them from possible non-neuronal cells or artifacts in the images. Here we investigate the performance of well-established machine learning techniques for this purpose. These include support vector machines, random forests, k-nearest neighbors, and generalized linear model classifiers, operating on an extensive set of image features extracted using the compound hierarchy of algorithms representing morphology, and the scale-invariant feature transform. We present experiments on a dataset of rat hippocampal neurons from our own studies to find the most suitable classifier(s) and subset(s) of features in the common practical setting where there is very limited annotated data for training. The results indicate that a random forests classifier using the right feature subset ranks best for the considered task, although its performance is not statistically significantly better than some support vector machine based classification models.
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Affiliation(s)
- Gadea Mata
- Department of Mathematics and Computer Science, University of La Rioja, Logroño, Spain.
| | - Miroslav Radojević
- Biomedical Imaging Group Rotterdam, Departments of Medical Informatics and Radiology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Carlos Fernandez-Lozano
- Department of Computer Science, University of A Coruña, A Coruña, Spain.,Instituto de Investigación Biomédica de A Coruña, Complexo Hospitalario Universitario de A Coruña, A Coruña, Spain
| | - Ihor Smal
- Biomedical Imaging Group Rotterdam, Departments of Medical Informatics and Radiology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Niels Werij
- Biomedical Imaging Group Rotterdam, Departments of Medical Informatics and Radiology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Miguel Morales
- Molecular Cognition Laboratory, Biophysics Institute, CSIC-UPV/EHU, Campus Universidad del País Vasco, Leioa, Spain
| | - Erik Meijering
- Biomedical Imaging Group Rotterdam, Departments of Medical Informatics and Radiology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Julio Rubio
- Department of Mathematics and Computer Science, University of La Rioja, Logroño, Spain
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8
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Asua D, Bougamra G, Calleja-Felipe M, Morales M, Knafo S. Peptides Acting as Cognitive Enhancers. Neuroscience 2017; 370:81-87. [PMID: 29030286 DOI: 10.1016/j.neuroscience.2017.10.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 09/25/2017] [Accepted: 10/02/2017] [Indexed: 10/18/2022]
Abstract
The aim of this paper is to present an overview of three peptides that, by improving synaptic function, enhance learning and memory in laboratory rodents. We summarize their structure, their mechanisms of action, and their effects on synaptic and cognitive function. First we describe FGL, a peptide derived from the neural cell adhesion molecule which improves cognition by the activation of the PKC pathway that triggers an activity-dependent delivery of AMPA receptors to the synapses. Then we describe PTD4-PI3KAc peptide that by activating PI3K signaling pathway it promotes synapse and spine formation and enhances hippocampal dependent memory. Lastly, we describe a new peptide derived from the well-known tumor suppressor PTEN that prevents pathological interactions between PTEN and PDZ proteins at synapses during exposure to Amyloid beta. This action prevents memory deterioration in mouse model of Alzheimer's disease. Together, this review indicates how learning and memory can be improved by manipulating synaptic function and number through pharmacological treatment with peptides, and it establishes synaptic function as a valid target for cognitive enhancement.
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Affiliation(s)
- Diego Asua
- Molecular Cognition Laboratory, Biophysics Institute, CSIC-UPV/EHU, Campus Universidad del País Vasco, Barrio Sarriena s/n, 48940 Leioa, Spain
| | - Ghassen Bougamra
- Molecular Cognition Laboratory, Biophysics Institute, CSIC-UPV/EHU, Campus Universidad del País Vasco, Barrio Sarriena s/n, 48940 Leioa, Spain
| | - María Calleja-Felipe
- Molecular Cognition Laboratory, Biophysics Institute, CSIC-UPV/EHU, Campus Universidad del País Vasco, Barrio Sarriena s/n, 48940 Leioa, Spain
| | - Miguel Morales
- Molecular Cognition Laboratory, Biophysics Institute, CSIC-UPV/EHU, Campus Universidad del País Vasco, Barrio Sarriena s/n, 48940 Leioa, Spain; Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Shira Knafo
- Molecular Cognition Laboratory, Biophysics Institute, CSIC-UPV/EHU, Campus Universidad del País Vasco, Barrio Sarriena s/n, 48940 Leioa, Spain; Ikerbasque, Basque Foundation for Science, Bilbao, Basque Country, Spain; Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel.
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9
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BAF53b, a Neuron-Specific Nucleosome Remodeling Factor, Is Induced after Learning and Facilitates Long-Term Memory Consolidation. J Neurosci 2017; 37:3686-3697. [PMID: 28270570 DOI: 10.1523/jneurosci.3220-16.2017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 01/31/2017] [Accepted: 03/01/2017] [Indexed: 11/21/2022] Open
Abstract
Although epigenetic mechanisms of gene expression regulation have recently been implicated in memory consolidation and persistence, the role of nucleosome-remodeling is largely unexplored. Recent studies show that the functional loss of BAF53b, a postmitotic neuron-specific subunit of the BAF nucleosome-remodeling complex, results in the deficit of consolidation of hippocampus-dependent memory and cocaine-associated memory in the rodent brain. However, it is unclear whether BAF53b expression is regulated during memory formation and how BAF53b regulates fear memory in the amygdala, a key brain site for fear memory encoding and storage. To address these questions, we used viral vector approaches to either decrease or increase BAF53b function specifically in the lateral amygdala of adult mice in auditory fear conditioning paradigm. Knockdown of Baf53b before training disrupted long-term memory formation with no effect on short-term memory, basal synaptic transmission, and spine structures. We observed in our qPCR analysis that BAF53b was induced in the lateral amygdala neurons at the late consolidation phase after fear conditioning. Moreover, transient BAF53b overexpression led to persistently enhanced memory formation, which was accompanied by increase in thin-type spine density. Together, our results provide the evidence that BAF53b is induced after learning, and show that such increase of BAF53b level facilitates memory consolidation likely by regulating learning-related spine structural plasticity.SIGNIFICANCE STATEMENT Recent works in the rodent brain begin to link nucleosome remodeling-dependent epigenetic mechanism to memory consolidation. Here we show that BAF53b, an epigenetic factor involved in nucleosome remodeling, is induced in the lateral amygdala neurons at the late phase of consolidation after fear conditioning. Using specific gene knockdown or overexpression approaches, we identify the critical role of BAF53b in the lateral amygdala neurons for memory consolidation during long-term memory formation. Our results thus provide an idea about how nucleosome remodeling can be regulated during long-term memory formation and contributes to the permanent storage of associative fear memory in the lateral amygdala, which is relevant to fear and anxiety-related mental disorders.
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Lou J, Teng Z, Zhang L, Yang J, Ma L, Wang F, Tian X, An R, Yang M, Zhang Q, Xu L, Dong Z. β-Caryophyllene/Hydroxypropyl-β-Cyclodextrin Inclusion Complex Improves Cognitive Deficits in Rats with Vascular Dementia through the Cannabinoid Receptor Type 2 -Mediated Pathway. Front Pharmacol 2017; 8:2. [PMID: 28154534 PMCID: PMC5243824 DOI: 10.3389/fphar.2017.00002] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 01/03/2017] [Indexed: 01/01/2023] Open
Abstract
This work was conducted to prepare β-caryophyllene-hydroxypropyl-β-cyclodextrin inclusion complex (HPβCD/BCP) and investigate its effects and mechanisms on cognitive deficits in vascular dementia (VD) rats. First, HPβCD/BCP was prepared, optimized, characterized, and evaluated. HPβCD/BCP and AM630 were then administered to VD rats to upregulate and downregulate the cannabinoid receptor type 2 (CB2). Results showed that HPβCD/BCP can significantly increase the bioavailability of BCP. Through the Morris water maze test, HPβCD/BCP can attenuate learning and memory deficits in rats. Cerebral blood flow (CBF) monitoring results indicated that HPβCD/BCP can promote the recovery of CBF. Moreover, molecular biology experiments showed that HPβCD/BCP can increase the expression levels of CB2 in brain tissues, particularly the hippocampus and white matter tissues, as well as the expression levels of PI3K and Akt. Overall, the findings demonstrated the protective effects of HPβCD/BCP against cognitive deficits induced by chronic cerebral ischemia and suggested the potential of HPβCD/BCP in the therapy of vascular dementia in the future.
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Affiliation(s)
- Jie Lou
- Chongqing Key Laboratory of Biochemistry and Molecular Pharmacology, School of Pharmacy, Chongqing Medical University Chongqing, China
| | - Zhipeng Teng
- Department of Neurosurgery, Chongqing Traditional Chinese Medicine Hospital Chongqing, China
| | - Liangke Zhang
- Chongqing Key Laboratory of Biochemistry and Molecular Pharmacology, School of Pharmacy, Chongqing Medical University Chongqing, China
| | - Jiadan Yang
- Department of Pharmacy, The First Affiliated Hospital of Chongqing Medical University Chongqing, China
| | - Lianju Ma
- The Experimental Teaching Center, Chongqing Medical University Chongqing, China
| | - Fang Wang
- Chongqing Key Laboratory of Biochemistry and Molecular Pharmacology, School of Pharmacy, Chongqing Medical University Chongqing, China
| | - Xiaocui Tian
- Chongqing Key Laboratory of Biochemistry and Molecular Pharmacology, School of Pharmacy, Chongqing Medical University Chongqing, China
| | - Ruidi An
- Chongqing Key Laboratory of Biochemistry and Molecular Pharmacology, School of Pharmacy, Chongqing Medical University Chongqing, China
| | - Mei Yang
- Chongqing Key Laboratory of Biochemistry and Molecular Pharmacology, School of Pharmacy, Chongqing Medical University Chongqing, China
| | - Qian Zhang
- Chongqing Key Laboratory of Biochemistry and Molecular Pharmacology, School of Pharmacy, Chongqing Medical University Chongqing, China
| | - Lu Xu
- Chongqing Key Laboratory of Biochemistry and Molecular Pharmacology, School of Pharmacy, Chongqing Medical University Chongqing, China
| | - Zhi Dong
- Chongqing Key Laboratory of Biochemistry and Molecular Pharmacology, School of Pharmacy, Chongqing Medical University Chongqing, China
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11
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Guegan T, Cebrià JP, Maldonado R, Martin M. Morphine-induced locomotor sensitization produces structural plasticity in the mesocorticolimbic system dependent on CB1-R activity. Addict Biol 2016; 21:1113-1126. [PMID: 26179931 DOI: 10.1111/adb.12281] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Changes in structural plasticity produced by the chronic exposure to drugs of abuse, such as alterations in dendritic spine densities, participate in the development of maladaptive learning processes leading to drug addiction. Understanding the neurobiological mechanisms involved in these aberrant changes is crucial to clarify the neurobiological substrate of addiction. Drug-induced locomotor sensitization has been widely accepted as a useful animal model to study these mechanisms related to drug addiction. We have evaluated the changes in structural plasticity in the mesocorticolimbic system involved in morphine-induced locomotor sensitization. The role of the cannabinoid receptor type 1 (CB1-R) in these neuroplastic alterations has also been studied using CB1-R-deficient (CB1-R KO) mice. Structural plasticity changes promoted by morphine are a highly dynamic phenomenon that evolves during the entire time course of the behavioral sensitization in wild-type (WT) animals. The different phases of the sensitization process were related to specific changes in connectivity between neurons revealed by modifications in dendritic spines in specific areas of the mesocorticolimbic system. Moreover, the lack of morphine-induced locomotor sensitization in CB1-R KO mice was accompanied by abnormal alterations in structural plasticity in the same mesocorticolimbic areas. These specific structural plasticity changes mediated by CB1-R activity seem necessary for the normal progression of morphine-induced locomotor sensitization and could play a critical role in the addictive process.
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Affiliation(s)
- Thomas Guegan
- Laboratory of Neuropharmacology; Parc de Recerca Biomèdica de Barcelona/Universitat Pompeu Fabra; Spain
| | - Joan Pau Cebrià
- Laboratory of Neuropharmacology; Parc de Recerca Biomèdica de Barcelona/Universitat Pompeu Fabra; Spain
| | - Rafael Maldonado
- Laboratory of Neuropharmacology; Parc de Recerca Biomèdica de Barcelona/Universitat Pompeu Fabra; Spain
| | - Miquel Martin
- Laboratory of Neuropharmacology; Parc de Recerca Biomèdica de Barcelona/Universitat Pompeu Fabra; Spain
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12
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Li C, Wang J, Zhao J, Wang Y, Liu Z, Guo FL, Wang XF, Vreugdenhil M, Lu CB. Atorvastatin enhances kainate-induced gamma oscillations in rat hippocampal slices. Eur J Neurosci 2016; 44:2236-46. [PMID: 27336700 DOI: 10.1111/ejn.13322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 06/16/2016] [Accepted: 06/21/2016] [Indexed: 01/16/2023]
Abstract
Atorvastatin has been shown to affect cognitive functions in rodents and humans. However, the underlying mechanism is not fully understood. Because hippocampal gamma oscillations (γ, 20-80 Hz) are associated with cognitive functions, we studied the effect of atorvastatin on persistent kainate-induced γ oscillation in the CA3 area of rat hippocampal slices. The involvement of NMDA receptors and multiple kinases was tested before and after administration of atorvastatin. Whole-cell current-clamp and voltage-clamp recordings were made from CA3 pyramidal neurons and interneurons before and after atorvastatin application. Atorvastatin increased γ power by ~ 50% in a concentration-dependent manner, without affecting dominant frequency. Whereas atorvastatin did not affect intrinsic properties of both pyramidal neurons and interneurons, it increased the firing frequency of interneurons but not that of pyramidal neurons. Furthermore, whereas atorvastatin did not affect synaptic current amplitude, it increased the frequency of spontaneous inhibitory post-synaptic currents, but did not affect the frequency of spontaneous excitatory post-synaptic currents. The atorvastatin-induced enhancement of γ oscillations was prevented by pretreatment with the PKA inhibitor H89, the ERK inhibitor U0126, or the PI3K inhibitor wortmanin, but not by the NMDA receptor antagonist D-AP5. Taken together, these results demonstrate that atorvastatin enhanced the kainate-induced γ oscillation by increasing interneuron excitability, with an involvement of multiple intracellular kinase pathways. Our study suggests that the classical cholesterol-lowering agent atorvastatin may improve cognitive functions compromised in disease, via the enhancement of hippocampal γ oscillations.
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Affiliation(s)
- Chengzhang Li
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, Henan, 453003, P.R. China
| | - Jiangang Wang
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, Henan, 453003, P.R. China
| | - Jianhua Zhao
- Department of Neurology, The First Affiliated Hospital of Xinxiang Medical University, Weihui, China
| | - Yali Wang
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, Henan, 453003, P.R. China
| | - Zhihua Liu
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, Henan, 453003, P.R. China
| | - Fang Li Guo
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, Henan, 453003, P.R. China
| | - Xiao Fang Wang
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, Henan, 453003, P.R. China
| | - Martin Vreugdenhil
- Department of Psychology, Xinxiang Medical University, Xinxiang, China.,School of Health and Education, Birmingham City University, Birmingham, UK
| | - Cheng Biao Lu
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, Henan, 453003, P.R. China
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13
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Cahill ME, Bagot RC, Gancarz AM, Walker DM, Sun H, Wang ZJ, Heller EA, Feng J, Kennedy PJ, Koo JW, Cates HM, Neve RL, Shen L, Dietz DM, Nestler EJ. Bidirectional Synaptic Structural Plasticity after Chronic Cocaine Administration Occurs through Rap1 Small GTPase Signaling. Neuron 2016; 89:566-82. [PMID: 26844834 DOI: 10.1016/j.neuron.2016.01.031] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 01/11/2016] [Accepted: 01/19/2016] [Indexed: 12/25/2022]
Abstract
Dendritic spines are the sites of most excitatory synapses in the CNS, and opposing alterations in the synaptic structure of medium spiny neurons (MSNs) of the nucleus accumbens (NAc), a primary brain reward region, are seen at early versus late time points after cocaine administration. Here we investigate the time-dependent molecular and biochemical processes that regulate this bidirectional synaptic structural plasticity of NAc MSNs and associated changes in cocaine reward in response to chronic cocaine exposure. Our findings reveal key roles for the bidirectional synaptic expression of the Rap1b small GTPase and an associated local synaptic protein translation network in this process. The transcriptional mechanisms and pathway-specific inputs to NAc that regulate Rap1b expression are also characterized. Collectively, these findings provide a precise mechanism by which nuclear to synaptic interactions induce "metaplasticity" in NAc MSNs, and we reveal the specific effects of this plasticity on reward behavior in a brain circuit-specific manner.
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Affiliation(s)
- Michael E Cahill
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Rosemary C Bagot
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Amy M Gancarz
- Department of Pharmacology and Toxicology, Research Institute on Addictions, Program in Neuroscience, State University of New York at Buffalo, Buffalo, NY 14214, USA
| | - Deena M Walker
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - HaoSheng Sun
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Zi-Jun Wang
- Department of Pharmacology and Toxicology, Research Institute on Addictions, Program in Neuroscience, State University of New York at Buffalo, Buffalo, NY 14214, USA
| | - Elizabeth A Heller
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jian Feng
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Pamela J Kennedy
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ja Wook Koo
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Hannah M Cates
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Rachael L Neve
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Li Shen
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - David M Dietz
- Department of Pharmacology and Toxicology, Research Institute on Addictions, Program in Neuroscience, State University of New York at Buffalo, Buffalo, NY 14214, USA
| | - Eric J Nestler
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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14
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Pen Y, Borovok N, Reichenstein M, Sheinin A, Michaelevski I. Membrane-tethered AKT kinase regulates basal synaptic transmission and early phase LTP expression by modulation of post-synaptic AMPA receptor level. Hippocampus 2016; 26:1149-67. [PMID: 27068236 DOI: 10.1002/hipo.22597] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/28/2016] [Indexed: 01/17/2023]
Abstract
The serine/threonine kinase AKT/PKB plays a fundamental role in a wide variety of neuronal functions, including neuronal cell development, axonal growth, and synaptic plasticity. Multiple evidence link AKT signaling pathways to regulation of late phase long-term synaptic plasticity, synaptogenesis, and spinogenesis, as well as long-term memory formation. Nevertheless, the downstream effectors mediating the effects of AKT on early phase long-term potentiation (eLTP) are currently unknown. Here we report that using different regimes of pharmacological activation and inhibition of AKT activity in acute hippocampal slices, we found that AKT regulates the post-synaptic expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA) receptors affecting solely the expression of eLTP, with no effect on its induction and maintenance. We further show that both maintenance of basal synaptic activity and expression of eLTP require plasma membrane tethering by activated AKT and that basal synaptic activity may be regulated via the direct effects of AKT1 on the expression level of post-synaptic AMPA receptors bypassing the canonical AKT signaling. Finally, we establish that eLTP expression requires the involvement of both the canonical AKT signaling pathways and the direct effect of AKT1 on AMPA receptor activity/expression in the post-synaptic membrane. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Y Pen
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel-Aviv, Israel
| | - N Borovok
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel-Aviv, Israel
| | - M Reichenstein
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel-Aviv, Israel
| | - A Sheinin
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel-Aviv, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel-Aviv, Israel
| | - I Michaelevski
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel-Aviv, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel-Aviv, Israel
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15
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Enriquez-Barreto L, Morales M. The PI3K signaling pathway as a pharmacological target in Autism related disorders and Schizophrenia. MOLECULAR AND CELLULAR THERAPIES 2016; 4:2. [PMID: 26877878 PMCID: PMC4751644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 01/25/2016] [Indexed: 11/21/2023]
Abstract
This review is focused in PI3K's involvement in two widespread mental disorders: Autism and Schizophrenia. A large body of evidence points to synaptic dysfunction as a cause of these diseases, either during the initial phases of brain synaptic circuit's development or later modulating synaptic function and plasticity. Autism related disorders and Schizophrenia are complex genetic conditions in which the identification of gene markers has proved difficult, although the existence of single-gene mutations with a high prevalence in both diseases offers insight into the role of the PI3K signaling pathway. In the brain, components of the PI3K pathway regulate synaptic formation and plasticity; thus, disruption of this pathway leads to synapse dysfunction and pathological behaviors. Here, we recapitulate recent evidences that demonstrate the imbalance of several PI3K elements as leading causes of Autism and Schizophrenia, together with the plausible new pharmacological paths targeting this signaling pathway.
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Affiliation(s)
- Lilian Enriquez-Barreto
- Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Miguel Morales
- Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain
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16
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Enriquez-Barreto L, Morales M. The PI3K signaling pathway as a pharmacological target in Autism related disorders and Schizophrenia. MOLECULAR AND CELLULAR THERAPIES 2016; 4:2. [PMID: 26877878 PMCID: PMC4751644 DOI: 10.1186/s40591-016-0047-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 01/25/2016] [Indexed: 01/01/2023]
Abstract
This review is focused in PI3K’s involvement in two widespread mental disorders: Autism and Schizophrenia. A large body of evidence points to synaptic dysfunction as a cause of these diseases, either during the initial phases of brain synaptic circuit’s development or later modulating synaptic function and plasticity. Autism related disorders and Schizophrenia are complex genetic conditions in which the identification of gene markers has proved difficult, although the existence of single-gene mutations with a high prevalence in both diseases offers insight into the role of the PI3K signaling pathway. In the brain, components of the PI3K pathway regulate synaptic formation and plasticity; thus, disruption of this pathway leads to synapse dysfunction and pathological behaviors. Here, we recapitulate recent evidences that demonstrate the imbalance of several PI3K elements as leading causes of Autism and Schizophrenia, together with the plausible new pharmacological paths targeting this signaling pathway.
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Affiliation(s)
- Lilian Enriquez-Barreto
- Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Miguel Morales
- Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain
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17
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Hippocampal Dendritic Spines Are Segregated Depending on Their Actin Polymerization. Neural Plast 2016; 2016:2819107. [PMID: 26881098 PMCID: PMC4736993 DOI: 10.1155/2016/2819107] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 09/21/2015] [Accepted: 10/01/2015] [Indexed: 01/28/2023] Open
Abstract
Dendritic spines are mushroom-shaped protrusions of the postsynaptic membrane. Spines receive the majority of glutamatergic synaptic inputs. Their morphology, dynamics, and density have been related to synaptic plasticity and learning. The main determinant of spine shape is filamentous actin. Using FRAP, we have reexamined the actin dynamics of individual spines from pyramidal hippocampal neurons, both in cultures and in hippocampal organotypic slices. Our results indicate that, in cultures, the actin mobile fraction is independently regulated at the individual spine level, and mobile fraction values do not correlate with either age or distance from the soma. The most significant factor regulating actin mobile fraction was the presence of astrocytes in the culture substrate. Spines from neurons growing in the virtual absence of astrocytes have a more stable actin cytoskeleton, while spines from neurons growing in close contact with astrocytes show a more dynamic cytoskeleton. According to their recovery time, spines were distributed into two populations with slower and faster recovery times, while spines from slice cultures were grouped into one population. Finally, employing fast lineal acquisition protocols, we confirmed the existence of loci with high polymerization rates within the spine.
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18
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Puigdellívol M, Cherubini M, Brito V, Giralt A, Suelves N, Ballesteros J, Zamora-Moratalla A, Martín ED, Eipper BA, Alberch J, Ginés S. A role for Kalirin-7 in corticostriatal synaptic dysfunction in Huntington's disease. Hum Mol Genet 2015; 24:7265-85. [PMID: 26464483 DOI: 10.1093/hmg/ddv426] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 10/05/2015] [Indexed: 01/09/2023] Open
Abstract
Cognitive dysfunction is an early clinical hallmark of Huntington's disease (HD) preceding the appearance of motor symptoms by several years. Neuronal dysfunction and altered corticostriatal connectivity have been postulated to be fundamental to explain these early disturbances. However, no treatments to attenuate cognitive changes have been successful: the reason may rely on the idea that the temporal sequence of pathological changes is as critical as the changes per se when new therapies are in development. To this aim, it becomes critical to use HD mouse models in which cognitive impairments appear prior to motor symptoms. In this study, we demonstrate procedural memory and motor learning deficits in two different HD mice and at ages preceding motor disturbances. These impairments are associated with altered corticostriatal long-term potentiation (LTP) and specific reduction of dendritic spine density and postsynaptic density (PSD)-95 and spinophilin-positive clusters in the cortex of HD mice. As a potential mechanism, we described an early decrease of Kalirin-7 (Kal7), a guanine-nucleotide exchange factor for Rho-like small GTPases critical to maintain excitatory synapse, in the cortex of HD mice. Supporting a role for Kal7 in HD synaptic deficits, exogenous expression of Kal7 restores the reduction of excitatory synapses in HD cortical cultures. Altogether, our results suggest that cortical dysfunction precedes striatal disturbances in HD and underlie early corticostriatal LTP and cognitive defects. Moreover, we identified diminished Kal7 as a key contributor to HD cortical alterations, placing Kal7 as a molecular target for future therapies aimed to restore corticostriatal function in HD.
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Affiliation(s)
- Mar Puigdellívol
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain, CIBERNED, Madrid, Spain
| | - Marta Cherubini
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain, CIBERNED, Madrid, Spain
| | - Verónica Brito
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain, CIBERNED, Madrid, Spain
| | - Albert Giralt
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain, CIBERNED, Madrid, Spain
| | - Núria Suelves
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain, CIBERNED, Madrid, Spain
| | - Jesús Ballesteros
- Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCYTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, Albacete, Spain and
| | - Alfonsa Zamora-Moratalla
- Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCYTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, Albacete, Spain and
| | - Eduardo D Martín
- Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCYTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, Albacete, Spain and
| | - Betty A Eipper
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, USA
| | - Jordi Alberch
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain, CIBERNED, Madrid, Spain
| | - Silvia Ginés
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain, CIBERNED, Madrid, Spain,
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19
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Enhanced memory consolidation in mice lacking the circadian modulators Sharp1 and -2 caused by elevated Igf2 signaling in the cortex. Proc Natl Acad Sci U S A 2015; 112:E3582-9. [PMID: 26100875 DOI: 10.1073/pnas.1423989112] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The bHLH transcription factors SHARP1 and SHARP2 are partially redundant modulators of the circadian system. SHARP1/DEC2 has been shown to control sleep length in humans and sleep architecture is also altered in double mutant mice (S1/2(-/-)). Because of the importance of sleep for memory consolidation, we investigated the role of SHARP1 and SHARP2 in cognitive processing. S1/2(-/-) mice show enhanced cortex (Cx)-dependent remote fear memory formation as well as improved reversal learning, but do not display alterations in hippocampus (Hi)-dependent recent fear memory formation. SHARP1 and SHARP2 single null mutants do not display any cognitive phenotype supporting functional redundancy of both factors. Molecular and biochemical analyses revealed elevated insulin-related growth factor 2 (IGF2) signaling and increased phosphorylation of MAPK and S6 in the Cx but not the Hi of S1/2(-/-) mice. No changes were detected in single mutants. Moreover, adeno-associated virus type 2-mediated IGF2 overexpression in the anterior cingulate cortex enhanced remote fear memory formation and the analysis of forebrain-specific double null mutants of the Insulin and IGF1 receptors revealed their essential function for memory formation. Impaired fear memory formation in aged S1/2(-/-) mice indicates that elevated IGF2 signaling in the long term, however, has a negative impact on cognitive processing. In summary, we conclude that the bHLH transcription factors SHARP1 and SHARP2 are involved in cognitive processing by controlling Igf2 expression and associated signaling cascades. Our analyses provide evidence that the control of sleep and memory consolidation may share common molecular mechanisms.
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20
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Cuesto G, Jordán-Álvarez S, Enriquez-Barreto L, Ferrús A, Morales M, Acebes Á. GSK3β inhibition promotes synaptogenesis in Drosophila and mammalian neurons. PLoS One 2015; 10:e0118475. [PMID: 25764078 PMCID: PMC4357437 DOI: 10.1371/journal.pone.0118475] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 01/17/2015] [Indexed: 01/22/2023] Open
Abstract
The PI3K-dependent activation of AKT results in the inhibition of GSK3β in most signaling pathways. These kinases regulate multiple neuronal processes including the control of synapse number as shown for Drosophila and rodents. Alzheimer disease's patients exhibit high levels of circulating GSK3β and, consequently, pharmacological strategies based on GSK3β antagonists have been designed. The approach, however, has yielded inconclusive results so far. Here, we carried out a comparative study in Drosophila and rats addressing the role of GSK3β in synaptogenesis. In flies, the genetic inhibition of the shaggy-encoded GSK3β increases the number of synapses, while its upregulation leads to synapse loss. Likewise, in three weeks cultured rat hippocampal neurons, the pharmacological inhibition of GSK3β increases synapse density and Synapsin expression. However, experiments on younger cultures (12 days) yielded an opposite effect, a reduction of synapse density. This unexpected finding seems to unveil an age- and dosage-dependent differential response of mammalian neurons to the stimulation/inhibition of GSK3β, a feature that must be considered in the context of human adult neurogenesis and pharmacological treatments for Alzheimer's disease based on GSK3β antagonists.
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Affiliation(s)
- Germán Cuesto
- Structural Synaptic Plasticity Laboratory, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de La Rioja, Logroño, La Rioja, Spain
| | - Sheila Jordán-Álvarez
- Department of Cellular, Molecular and Developmental Neurobiology, Cajal Institute, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Lilian Enriquez-Barreto
- Structural Synaptic Plasticity Laboratory, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de La Rioja, Logroño, La Rioja, Spain
| | - Alberto Ferrús
- Department of Cellular, Molecular and Developmental Neurobiology, Cajal Institute, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Miguel Morales
- Structural Synaptic Plasticity Laboratory, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de La Rioja, Logroño, La Rioja, Spain
- * E-mail: (AA); (MM)
| | - Ángel Acebes
- Department of Cellular, Molecular and Developmental Neurobiology, Cajal Institute, Consejo Superior de Investigaciones Científicas, Madrid, Spain
- * E-mail: (AA); (MM)
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21
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Middei S, Ammassari-Teule M, Marie H. Synaptic plasticity under learning challenge. Neurobiol Learn Mem 2014; 115:108-15. [DOI: 10.1016/j.nlm.2014.08.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 08/01/2014] [Accepted: 08/06/2014] [Indexed: 10/24/2022]
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22
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Brito V, Giralt A, Enriquez-Barreto L, Puigdellívol M, Suelves N, Zamora-Moratalla A, Ballesteros JJ, Martín ED, Dominguez-Iturza N, Morales M, Alberch J, Ginés S. Neurotrophin receptor p75(NTR) mediates Huntington's disease-associated synaptic and memory dysfunction. J Clin Invest 2014; 124:4411-28. [PMID: 25180603 PMCID: PMC4191006 DOI: 10.1172/jci74809] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 07/29/2014] [Indexed: 12/13/2022] Open
Abstract
Learning and memory deficits are early clinical manifestations of Huntington's disease (HD). These cognitive impairments have been mainly associated with frontostriatal HD pathology; however, compelling evidence provided by several HD murine models suggests that the hippocampus may contribute to synaptic deficits and memory dysfunction in HD. The neurotrophin receptor p75(NTR) negatively regulates spine density, which is associated with learning and memory; therefore, we explored whether disturbed p75(NTR) function in the hippocampus could contribute to synaptic dysfunction and memory deficits in HD. Here, we determined that levels of p75(NTR) are markedly increased in the hippocampus of 2 distinct mouse models of HD and in HD patients. Normalization of p75(NTR) levels in HD mutant mice heterozygous for p75(NTR) prevented memory and synaptic plasticity deficits and ameliorated dendritic spine abnormalities, likely through normalization of the activity of the GTPase RhoA. Moreover, viral-mediated overexpression of p75(NTR) in the hippocampus of WT mice reproduced HD learning and memory deficits, while knockdown of p75(NTR) in the hippocampus of HD mice prevented cognitive decline. Together, these findings provide evidence of hippocampus-associated memory deficits in HD and demonstrate that p75(NTR) mediates synaptic, learning, and memory dysfunction in HD.
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Affiliation(s)
- Verónica Brito
- Departament de Biologia Celηlular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain. Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain. Structural Synaptic Plasticity Lab, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de la Rioja, La Rioja, Spain. Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCyTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, Albacete, Spain
| | - Albert Giralt
- Departament de Biologia Celηlular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain. Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain. Structural Synaptic Plasticity Lab, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de la Rioja, La Rioja, Spain. Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCyTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, Albacete, Spain
| | - Lilian Enriquez-Barreto
- Departament de Biologia Celηlular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain. Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain. Structural Synaptic Plasticity Lab, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de la Rioja, La Rioja, Spain. Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCyTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, Albacete, Spain
| | - Mar Puigdellívol
- Departament de Biologia Celηlular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain. Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain. Structural Synaptic Plasticity Lab, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de la Rioja, La Rioja, Spain. Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCyTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, Albacete, Spain
| | - Nuria Suelves
- Departament de Biologia Celηlular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain. Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain. Structural Synaptic Plasticity Lab, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de la Rioja, La Rioja, Spain. Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCyTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, Albacete, Spain
| | - Alfonsa Zamora-Moratalla
- Departament de Biologia Celηlular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain. Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain. Structural Synaptic Plasticity Lab, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de la Rioja, La Rioja, Spain. Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCyTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, Albacete, Spain
| | - Jesús J. Ballesteros
- Departament de Biologia Celηlular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain. Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain. Structural Synaptic Plasticity Lab, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de la Rioja, La Rioja, Spain. Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCyTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, Albacete, Spain
| | - Eduardo D. Martín
- Departament de Biologia Celηlular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain. Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain. Structural Synaptic Plasticity Lab, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de la Rioja, La Rioja, Spain. Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCyTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, Albacete, Spain
| | - Nuria Dominguez-Iturza
- Departament de Biologia Celηlular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain. Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain. Structural Synaptic Plasticity Lab, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de la Rioja, La Rioja, Spain. Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCyTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, Albacete, Spain
| | - Miguel Morales
- Departament de Biologia Celηlular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain. Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain. Structural Synaptic Plasticity Lab, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de la Rioja, La Rioja, Spain. Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCyTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, Albacete, Spain
| | - Jordi Alberch
- Departament de Biologia Celηlular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain. Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain. Structural Synaptic Plasticity Lab, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de la Rioja, La Rioja, Spain. Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCyTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, Albacete, Spain
| | - Sílvia Ginés
- Departament de Biologia Celηlular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain. Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain. Structural Synaptic Plasticity Lab, Department of Neurodegenerative Diseases, Centro de Investigación Biomédica de la Rioja, La Rioja, Spain. Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCyTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, Albacete, Spain
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Caroni P, Chowdhury A, Lahr M. Synapse rearrangements upon learning: from divergent-sparse connectivity to dedicated sub-circuits. Trends Neurosci 2014; 37:604-14. [PMID: 25257207 DOI: 10.1016/j.tins.2014.08.011] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/26/2014] [Accepted: 08/27/2014] [Indexed: 01/24/2023]
Abstract
Learning can involve formation of new synapses and loss of synapses, providing memory traces of learned skills. Recent findings suggest that these synapse rearrangements reflect assembly of task-related sub-circuits from initially broadly distributed and sparse connectivity in the brain. These local circuit remodeling processes involve rapid emergence of synapses upon learning, followed by protracted validation involving strengthening of some new synapses, and selective elimination of others. The timing of these consolidation processes can vary. Here, we review these findings, focusing on how molecular/cellular mechanisms of synapse assembly, strengthening, and elimination might interface with circuit/system mechanisms of learning and memory consolidation. An integrated understanding of these learning-related processes should provide a better basis to elucidate how experience, genetic background, and disease influence brain function.
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Affiliation(s)
- Pico Caroni
- Friedrich Miescher Institut, Basel, Switzerland.
| | | | - Maria Lahr
- Friedrich Miescher Institut, Basel, Switzerland
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24
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Kim SW, Cho KJ. Activity-dependent alterations in the sensitivity to BDNF-TrkB signaling may promote excessive dendritic arborization and spinogenesis in fragile X syndrome in order to compensate for compromised postsynaptic activity. Med Hypotheses 2014; 83:429-35. [PMID: 25113167 DOI: 10.1016/j.mehy.2014.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Accepted: 07/11/2014] [Indexed: 12/20/2022]
Abstract
Fragile X syndrome (FXS), the most common cause of inherited human mental retardation, results from the loss of function of fragile X mental retardation protein (FMRP). To date, most researchers have thought that FXS neural pathologies are primarily caused by extreme dendritic branching and spine formation. With this rationale, several researchers attempted to prune dendritic branches and reduce the number of spines in FXS animal models. We propose that increased dendritic arborization and spinogenesis in FXS are developed rather as secondary compensatory responses to counteract the compromised postsynaptic activity during uncontrollable metabotropic glutamate receptor (mGluR)-dependent long-term depression (LTD). When postsynaptic and electrical activities become dampened in FXS, dendritic trees can increase their sensitivity to brain-derived neurotrophic factor (BDNF) by using the molecular sensor called eukaryotic elongation factor 2 (eEF2) and taking advantage of the tight coupling of mGluR and BDNF-TrkB signaling pathways. Then, this activity-dependent elevation of the BDNF signaling can strategically alter dendritic morphologies to foster branching and develop spine structures in order to improve the postsynaptic response in FXS. Our model suggests a new therapeutic rationale for FXS: correcting the postsynaptic and electrical activity first, and then repairing structural abnormalities of dendrites. Then, it may be possible to successfully fix the dendritic morphologies without affecting the survival of neurons. Our theory may also be generalized to explain aberrant dendritic structures observed in other neurobehavioral diseases, such as tuberous sclerosis, Rett syndrome, schizophrenia, and channelopathies, which accompany high postsynaptic and electrical activity.
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Affiliation(s)
- Sang Woo Kim
- Department of Neuroscience, Brown University, Providence, RI 02912, United States.
| | - Kyoung Joo Cho
- Department of Anatomy, BK 21 PLUS for Medical Science, College of Medicine, Yonsei University, Seoul, South Korea.
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